Both institutional and consumer automatic dishwashers or warewashing machines have been in use for many years. These dishwashers typically function with one or more steps during a cleaning cycle. The cycle includes various combinations of a soak or a presoak process, a main detergent wash process, a rinse process, and a high temperature or chemical sanitizing rinse process. A dishwasher detergent composition is typically utilized during the main detergent wash process to remove soils and stains. Often, the detergent composition will include water softeners or sequesterants, bleaching and sanitizing agents, and an alkali source. Glasses and other wares washed in automatic washing machines are preferably obtained without food soils and without residue from the cleaning solutions or other chemicals used in the detergent wash process.
One type of residue, known as protein deposition, is common on machine washed dishes. Glasses and other ware washed in automatic dishwashing machines commonly include left on food soils. Often the detergent composition alone is not able to fully remove all protein depositions and food soils remain on the surface of the wares even after they have been through the detergent wash process.
A second type of residue, known as streaking and spotting, is also common on machine washed dishes. Streaking and spotting is believed to result when water salts deposit on the dishes after the rinse drainage and evaporation. Glasses and other ware washed in automatic dishwashing machines commonly include residue from the cleaning solutions or other chemicals used in the detergent wash process. Rinse additives or aids are commonly added to rinse water in an effort to reduce surface tension of the rinse water and thereby promote sheeting of the water from the dishes. Typical rinse aid formulas require solution concentrations ranging from about 10 ppm to 100 ppm (depending on actives) to provide efficient sheeting and drying.
In general, rinse aids minimize spotting and promote faster drying by causing the rinse water to sheet off of the clean dishes and other wares evenly and quickly. Rinse aids are generally used after the detergent composition.
A substantial need exists for a method of removing protein residue and preventing redeposition of protein soils at relatively low solution concentrations without leaving any residue from the cleaning solutions or other chemicals used in the detergent wash process.